1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
laila [671]
3 years ago
9

Assume that the mass has been moving along its circular path for some time. You start timing its motion with a stopwatch when it

crosses the positive x axis, an instant that corresponds to t=0. [Notice that when t=0, r⃗ (t=0)=Ri^.] For the remainder of this problem, assume that the time t is measured from the moment you start timing the motion. Then the time − t refers to the moment a time t before you start your stopwatch.
What is the velocity of the mass at a time − t?
Express this velocity in terms of R, ω, t, and the unit vectors i^ and j^.
Physics
1 answer:
lesya692 [45]3 years ago
6 0

Answer:

v = R\omega(-sin\omega t \hat i + cos\omega t \hat j)

Explanation:

As we know that the mass is revolving with constant angular speed in the circle of radius R

So we will have

\theta = \omega t

now the position vector at a given time is

r = Rcos\theta \hat i + R sin\theta \hat j

now the linear velocity is given as

v = \frac{dr}{dt}

v = (-R sin\theta \hat i + R cos\theta \hat j)\frac{d\theta}{dt}

v = R\omega(-sin\omega t \hat i + cos\omega t \hat j)

You might be interested in
How much heat is required to evaporate 0.15 kg of lead at 1750°C, the boiling point for lead? The heat of vaporization for lead
lara [203]

Answer:

Heat required = mass× latent heat Q = 0.15 × 871 ×

3 0
3 years ago
A train whistle is heard at 300 Hz as the train approaches town. The train cuts its speed in half as it nears the station, and t
givi [52]

To solve this problem we will apply the concepts related to the Doppler effect. The Doppler effect is the change in the perceived frequency of any wave movement when the emitter, or focus of waves, and the receiver, or observer, move relative to each other. Mathematically it can be described as,

f = f_0 (\frac{v_0}{v_0-v})

Here,

f_0 = Frequency of Source

v_s = Speed of sound

f = Frequency heard before slowing down

f' = Frequency heard after slowing down

v  = Speed of the train before slowing down

So if the speed of the train after slowing down will be v/2, we can do a system equation of 2x2 at the two moments, then,

The first equation is,

f = f_0 (\frac{v_0}{v_0-v})

300 = f_0 (\frac{343}{343-v})

(300*343) - 300v = 343f_0

Now the second expression will be,

f' = f_0 (\frac{v_0}{v_0-v/2})

290 = (343)(\frac{v_0}{343-v/2})

290*343-145v = 343f_0

Dividing the two expression we have,

\frac{(300*343) - 300v}{290*343-145v} = 1

Solving for v, we have,

v = 22.12m/s

Therefore the speed of the train before and after slowing down is 22.12m/s

6 0
3 years ago
I NEED HELP ASAP!!!
Savatey [412]
I think option C is correct..hope it helps
3 0
2 years ago
Read 2 more answers
6. Velocity is a ____________. a) vector b) value c) arrow d) none of these
Olenka [21]
<span>the speed of something in a given direction.   so i think none of these</span>
4 0
3 years ago
Read 2 more answers
A force of 200N due South and another force of 300N due East each act on an object simultaneously.
dangina [55]

Answer:

a) 500

b)-500, north west

Explanation:

a) sum of F= F1+F2= 200+300= 500

b) sum of forces=0

so 200+300-500+0

4 0
2 years ago
Other questions:
  • Why should a tennis player "swing through" when hitting a tennis ball?​
    10·1 answer
  • Please help!!................
    13·1 answer
  • A Honda Civic travels in a straight line along a road. The car’s distance x from a stop sign is given as a function of time t by
    7·1 answer
  • When a fluid is heated, what changes occur?
    13·1 answer
  • In a downtown office building, you notice each of the four sections of a rotating door has a mass of 75 kg. What is the width, i
    11·1 answer
  • A machine has mechanical advantage 2.What does that mean​
    12·2 answers
  • A 25.0 kg object is held 8.50 m above the ground. Calculate its PE
    14·1 answer
  • Can someone help me due at 1:00 PM plus 100 points <br><br>questions B,C,D
    12·2 answers
  • How is energy transferred and transformed? and examples with full explanation.
    7·1 answer
  • Two forces act on wooden box with mass of (30kg) (if F1,=85.7N east and F270.7N west):
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!